Open Access Original Research Article

A Facile Synthesis of 7-amino-1,3-diaryl-5-phenyl-2-thioxo-pyrano[2,3-d]pyrimidine-4(5H)-ones

Nimalini Moirangthem, Warjeet S. Laitonjam

Chemical Science International Journal, Page 58-70
DOI: 10.9734/ACSJ/2011/345

The reactions of arylidene derivatives such as ethylphenylmethylenemalononitrile 3a, ethylphenylmethylenecyanoacetate 3b and ethylphenylmethylenecyano-acetamide 3c with substituted thiobarbituric acids 2a-e in presence of NaOCH3 and MeOH afforded 7-amino-1,3-diaryl-5-phenyl-2-thioxo-pyrano[2,3-d]pyrimidin-4(5H)ones 4a-e and 5e by cyclocondensation.

Open Access Original Research Article

Correlation of Photosubstitution Quantum Efficiencies of [Cr Lm Cln](3-n)+ Complexes with Solvent Properties in Mixed Solvents by Statistical Relationships

A. Rajendran, K. Anbalagan

Chemical Science International Journal, Page 71-88
DOI: 10.9734/ACSJ/2011/261

Objectives: This investigation focuses on the excited state aquation reactions of a series of [Cr(N)xCly](3-y)+ [(N)x = (en)2, (pn)2, (tn)2, (dien), (trien) and (tetren)] complexes in binary solvent(methanol/water) media. The main objective of this paper is to study the quantum yield (Φ) variation with respect to change of mole fraction (x2)of solvents in aquation reactions of these Cr (III) complexes in mixed solvent media and to interpret the results in the light of statistical analysis to give meaningful qualitative and quantitative treatment.
Study design: The linear solvation energy relationship (LSER) is employed to correlate the Φ data with various empirical solvent parameters in single and multiple statistical equations.
Methodology: Visible light photolysis was carried out for the [Cr Lm Cln](3-n)+ complexes in water containing either methanol (MeOH) or 1,4-dioxane (Diox), x2 (xMeOH/xDiox) 0, 0.029/0.0109 to 0.1602/0.0831, respectively.
Results: Photolysis of these complexes in these binary mixtures is good to excellent for few complexes and poor for the remaining cases. Solvent assisted photolysis in the binary solvent mixtures produced aquated products. In principle, the photoaquation takes place by associative mechanism and quantum yield for this reaction was found to exhibit linear x2 dependence.
Conclusion: In summary, the available model analysis allows a definitive choice of the above two alternative pathways according an increase or decrease in Φ value at higher mole fractions of MeOH/Diox in the medium. This conclusion is more appealing and in order to gain more insight into the problem. This model analysis is extremely important because it can yield both qualitative (bulk solvent effect) and quantitative (short range solvation effect) information that may otherwise be difficult to arrive at.

Open Access Original Research Article

A Comparative Study of the Adsorptive Characteristics of Mucin to Calcium Hydroxyapatite and Titanium Implants

Omoniyi Kehinde Israel, Ekwumemgbo Adamma Patricia, Emmanuel Echiobi Gaba, Adewusi Adeola Mary

Chemical Science International Journal, Page 89-96
DOI: 10.9734/ACSJ/2011/289

Aims: The study is aimed to examine the adsorptive characteristics of the main salivary protein, mucin onto Ti surfaces and compare the scientific data with that onto CaHap; towards elucidating the biocompatibility of these two candidates in biomedical applications.
Place and Duration of Study: Department of Chemistry, Ahmadu Bello University, Zaria, Nigeria. Study was carried out between January and April, 2004.
Methodology: To 50 mg, 100 mg, 150 mg and 300 mg of Ti or CaHap powder, 10 mL of (1% or 5%) mucin solution already incubated at 37°C was added at a contact time of 45 minutes in an incubator. After discarding the supernatant, a 10 mL volume of doubly distilled water was added to each residue and rinsed to remove the unadsorbed mucin. The adsorbent particles with the adsorbed mucin of an experimental group was then heated to 60°C for five hours in an oven and then weighed. The samples were then placed in a muffle-furnace at 600°C for 30 minutes to remove the mucin by burning, so as to obtain the weight of adsorbed mucin.
For the experiment on the adsorptive strength, to seven sets of 500 mg Ti or CaHap powder 10 mL of 1% mucin solution was added in an incubator. After centrifugation, the supernatant solution above the titanium particles was removed from the precipitates, and 8 mL of distilled water incubated at 37°C added; after shaking, the supernatant was again removed by the same method. The same rinsing procedure as described above was repeated 0, 1, 2, 4, 8, 10 and 12 times in different experimental groups. The Ti or CaHap particles were heated to 60°C for 5 hours in an oven and weighed. The adsorptive strength was evaluated by comparing the weight change between the no rinse and multiple rinse samples.
One gramme of Ti or CaHap powder placed in test tubes was suspended in 1.0 mL of solutions containing 0.2 – 1.8 mg/mL mucin solution. Following constant shaking for 24 hours at 37°C, the suspensions were allowed to settle and the supernatants collected to determine the adsorption isotherms. Bradford assay was performed on 0.1 mL supernatant samples to obtain Langmuir adsorption isotherm for the materials.
Results: The amount of mucin adsorbed to CaHap was 1.79 ± 0.65 times higher than that to Ti. At the eighth rinse mucin particles remain adsorbed to CaHap but none on the Ti surfaces. The adsorption isotherms of mucin onto both materials exhibited the Langmuir adsorption isotherm, with a maximum of 0.14 mg mucin adsorbed/ 1.0 g CaHap powder compared to a maximum of 0.11 mg mucin/ 1.0 g Ti powder reported by Lori and Nok, (2004).
Conclusion: Mucin can be completely rinsed from the surfaces of artificial titanium tooth and braces deployed in the mouth, thereby prolonging the lifespan. Adsorption of mucin onto these two biomaterial surfaces exhibited the Langmuir type with similarity, so bio-engineered Ti-Hap composite has excellent biocompatibility. The results of these in vitro experiments were consistent with the proposal that ceramics have a higher adsorptive ability than do metals.

Open Access Original Research Article

Synthesis of Functionalized Iron Oxide Nanoparticle with Amino Pyridine Moiety and Studies on Their Catalytic Behavior

D. Girija, Halehatty S. Bhojya Naik, B. Vinay Kumar, C. N. Sudhamani

Chemical Science International Journal, Page 97-108
DOI: 10.9734/ACSJ/2011/437

Aim: The main objective of this paper is to study the synthesis of functionalized iron oxide nanoparticle and its reactivity towards chromene synthesis
Study design: Functionalized iron oxide nanoparticle study.
Place and duration of study: Department of Studies and Research in Industrial Chemistry, School of Chemical Sciences, Kuvempu University, Shankaraghatta, between December 2009 and July 2010.
Methodology: This paper describes synthesis of stable functionalized iron oxide nanoparticles through surface modification of magnetic iron oxide nanoparticles by amino pyridine. Iron oxide nanoparticles were synthesized by co-precipitation method and the surface modification process was achieved by treating the nanoparticles with (chloro propyl trimethoxy silane) CPTS and aminopyridine. The developed functionalized iron oxide nanoparticle was evaluated as the catalyst for synthesis of chromones under MW irradiation conditions.
Results: The catalysts were magnetically recovered and reusable without significant loss of their catalytic efficiency. To receive morphological and structural information on the obtained functionalized nanoparticle, the samples were analyzed by X-ray diffraction (XRD) measurements, FTIR and scanning electron microscopy (SEM) imaging. All synthesized chromene derivatives were characterized using analytical techniques such as IR, 1H NMR, and mass spectroscopy. Also the identity of these compounds was easily established by comparison of their melting point with those of reported samples
Conclusion: In summary, we have developed a new magnetically recyclable and efficient functionalized magnetic nano catalyst for the chromene synthesis. Magnetic nanoparticle catalyst achieves a simple separation of catalyst without filtration including high yield in product.